// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_MEDIA_MEDIA_INTERNALS_H_
#define CONTENT_BROWSER_MEDIA_MEDIA_INTERNALS_H_

#include <list>
#include <map>
#include <string>
#include <tuple>
#include <vector>

#include "base/callback_forward.h"
#include "base/compiler_specific.h"
#include "base/lazy_instance.h"
#include "base/macros.h"
#include "base/strings/string16.h"
#include "base/synchronization/lock.h"
#include "base/values.h"
#include "content/common/content_export.h"
#include "content/public/browser/notification_observer.h"
#include "content/public/browser/notification_registrar.h"
#include "media/audio/audio_logging.h"
#include "media/base/media_log.h"
#include "media/capture/video/video_capture_device_descriptor.h"
#include "media/capture/video_capture_types.h"

namespace media {
struct MediaLogEvent;
}

namespace content {

// This class stores information about currently active media.
class CONTENT_EXPORT MediaInternals
    : NON_EXPORTED_BASE(public media::AudioLogFactory),
      public NotificationObserver {
public:
    // Called with the update string.
    typedef base::Callback<void(const base::string16&)> UpdateCallback;

    static MediaInternals* GetInstance();

    ~MediaInternals() override;

    // NotificationObserver implementation.
    void Observe(int type,
        const NotificationSource& source,
        const NotificationDetails& details) override;

    // Called when a MediaEvent occurs.
    void OnMediaEvents(int render_process_id,
        const std::vector<media::MediaLogEvent>& events);

    // Add/remove update callbacks (see above). Must be called on the UI thread.
    // The callbacks must also be fired on UI thread.
    void AddUpdateCallback(const UpdateCallback& callback);
    void RemoveUpdateCallback(const UpdateCallback& callback);

    // Whether there are any update callbacks available. Can be called on any
    // thread.
    bool CanUpdate();

    // Replay all saved media events.
    void SendHistoricalMediaEvents();

    // Sends all audio cached data to each registered UpdateCallback.
    void SendAudioStreamData();

    // Sends all video capture capabilities cached data to each registered
    // UpdateCallback.
    void SendVideoCaptureDeviceCapabilities();

    // Called to inform of the capabilities enumerated for video devices.
    void UpdateVideoCaptureDeviceCapabilities(
        const std::vector<std::tuple<media::VideoCaptureDeviceDescriptor,
            media::VideoCaptureFormats>>&
            descriptors_and_formats);

    // AudioLogFactory implementation.  Safe to call from any thread.
    std::unique_ptr<media::AudioLog> CreateAudioLog(
        AudioComponent component) override;

    // If possible, i.e. a WebContents exists for the given RenderFrameHostID,
    // tells an existing AudioLogEntry the WebContents title for easier
    // differentiation on the UI.
    void SetWebContentsTitleForAudioLogEntry(int component_id,
        int render_process_id,
        int render_frame_id,
        media::AudioLog* audio_log);

private:
    // Inner class to handle reporting pipelinestatus to UMA
    class MediaInternalsUMAHandler;

    friend class AudioLogImpl;
    friend class MediaInternalsTest;
    friend struct base::DefaultLazyInstanceTraits<MediaInternals>;

    MediaInternals();

    // Sends |update| to each registered UpdateCallback.  Safe to call from any
    // thread, but will forward to the IO thread.
    void SendUpdate(const base::string16& update);

    // Saves |event| so that it can be sent later in SendHistoricalMediaEvents().
    void SaveEvent(int process_id, const media::MediaLogEvent& event);

    // Caches |value| under |cache_key| so that future UpdateAudioLog() calls
    // will include the current data.  Calls JavaScript |function|(|value|) for
    // each registered UpdateCallback (if any).
    enum AudioLogUpdateType {
        CREATE, // Creates a new AudioLog cache entry.
        UPDATE_IF_EXISTS, // Updates an existing AudioLog cache entry, does
        // nothing if it doesn't exist.
        UPDATE_AND_DELETE, // Deletes an existing AudioLog cache entry.
    };
    void UpdateAudioLog(AudioLogUpdateType type,
        const std::string& cache_key,
        const std::string& function,
        const base::DictionaryValue* value);

    // Must only be accessed on the UI thread.
    std::vector<UpdateCallback> update_callbacks_;

    // Saved events by process ID for showing recent players in the UI.
    std::map<int, std::list<media::MediaLogEvent>> saved_events_by_process_;

    // Must only be accessed on the IO thread.
    base::ListValue video_capture_capabilities_cached_data_;

    NotificationRegistrar registrar_;

    // All variables below must be accessed under |lock_|.
    base::Lock lock_;
    bool can_update_;
    base::DictionaryValue audio_streams_cached_data_;
    int owner_ids_[AUDIO_COMPONENT_MAX];
    std::unique_ptr<MediaInternalsUMAHandler> uma_handler_;

    DISALLOW_COPY_AND_ASSIGN(MediaInternals);
};

} // namespace content

#endif // CONTENT_BROWSER_MEDIA_MEDIA_INTERNALS_H_
